1. Field of the Invention
This invention relates generally to automotive tools and fixtures and more particularly, to fixtures for use in assembling and disassembling strut assemblies having a shock absorber axially disposed within a helical, coil spring.
2. Description of Prior Art
Certain types of automotive suspension systems, such as the MacPherson-type, include a suspension subassembly. The subassembly includes a shock absorber and a strut spring, and is often referred to as a strut assembly. The shock absorber or damper consists of a piston within the body of the shock absorber connected to a piston rod which projects upwardly from the shock absorber in a telescoping fashion. A coil spring is mounted in a compressed state around the piston rod and body of the shock absorber between a lower spring seat integral with the body of the absorber and an upper spring seat fastened to the upper end of the piston rod of the shock absorber. Such a suspension subassembly is mounted as a unit in the vehicle body and is disassembled, serviced, and reassembled separately.
Disassembly of the strut assembly is accomplished by compressing the coil spring using a suitable tool or fixture to remove pressure from the spring seats of the strut assembly. Having done so, the fastener holding the piston rod to the upper spring seat can be removed. This fastener variously takes the form of a nut or retaining ring which fastens above the upper spring seat to the piston rod retaining all components of the strut assembly. The shock absorber and lower spring seat can then be removed leaving the spring in a compressed state within the tool. If required, the spring can then be decompressed and removed. In most cases, the coil spring must be compressed by engaging the spring itself between the upper and lower spring seats rather than engaging the upper spring seat and spring.
New or serviced components can be reassembled following the reverse of the foregoing process. Namely, with the spring in a compressed state, the shock absorber is placed axially through the spring such that the piston rod protrudes beyond the coil spring upper end and the lower spring seat contacts the lower end of the compressed spring. The appropriate fastener is attached to the piston rod above the upper spring seat. The strut assembly is then gradually released from the tool and is ready for reinstallation in the vehicle.
Numerous apparatus have been developed to assist in the assembly and disassembly of a strut suspension system, but with the design and development of newer and different types of strut assemblies, it has become desirable to have an apparatus which can accept a wide variety of different types of strut assemblies and different types and sizes of MacPherson strut assemblies without the use of adapters or an overly bulky structure. It is also desirable that the apparatus is able to be quickly adapted by the operator to accept a particular sized strut assembly for quick and efficient assembling and disassembling. It is also important to ensure that the apparatus can securely engage and retain a spring to ensure the safety of an operator because the springs are compressed under a large force which, if released without control, could injure an operator and damage property.